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Title: Turbulent transport regimes and the scrape-off layer heat flux width

Understanding the responsible mechanisms and resulting scaling of the scrape-off layer (SOL) heat flux width is important for predicting viable operating regimes in future tokamaks and for seeking possible mitigation schemes. In this paper, we present a qualitative and conceptual framework for understanding various regimes of edge/SOL turbulence and the role of turbulent transport as the mechanism for establishing the SOL heat flux width. Relevant considerations include the type and spectral characteristics of underlying instabilities, the location of the gradient drive relative to the SOL, the nonlinear saturation mechanism, and the parallel heat transport regime. We find a heat flux width scaling with major radius R that is generally positive, consistent with the previous findings [Connor et al., Nucl. Fusion 39, 169 (1999)]. The possible relationship of turbulence mechanisms to the neoclassical orbit width or heuristic drift mechanism in core energy confinement regimes known as low (L) mode and high (H) mode is considered, together with implications for the future experiments.
Authors:
; ;  [1]
  1. Lodestar Research Corporation, Boulder, Colorado 80301 (United States)
Publication Date:
OSTI Identifier:
22408324
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; EXPERIMENT PLANNING; HEAT FLUX; HEAT TRANSFER; H-MODE PLASMA CONFINEMENT; L-MODE PLASMA CONFINEMENT; NONLINEAR PROBLEMS; PLASMA INSTABILITY; PLASMA SCRAPE-OFF LAYER; SCALING; TOKAMAK DEVICES; TURBULENCE